Screen grating for the simultaneous two-directional transmission of ultra-short waves



Dec. 5, 1933.

SCREEN GRATING FOR THE SIMULTANEOUS TWO-DIRECTIONAL TRANSMISSION OF ULTRA-SHORT WAVES R. H. DARBORD Filed July 10, 1931 INVENTOR RENE H. DARBORD ATTOR Y.

respect to'eaoh'others; .7

it: e the'p'iirpio'ses of transmission. anderec'eption.

f f. Heretofore it has been necessary t'ouse difierent reflectors for transmission andreice'ptionfi As the cost or reflector s. is high in comparison-with the other elenientsoiannltra shortwave system, it is desirable, n for economicali'reasons, ,to' reduce the Thefprincipal object er the praem veiim is;

i 'to prov'i de means for utilizing a single'reflector for iooth the-transmission and reception."

' 1 Another object is to' providejtwo-channel transmission in one directionbetween" atransmitting and a receiving point by the use of a single re flect'or located ateach ofthe se points.

' fin carrying outthe bove'ementionedobjeetsja J p o I defined as that point on the axis of'the reflec p screen grating is properly disposed between the two elements associated;witheachireflector and the planes'of polarization 'of the several elements are suitably crossed; ,With this arrangement,,.the

screen grating prevents interference between'the 1 .twofelements associatedwith each of the reflectors; and thus 'permits'fltwochannel' communica tion; to .be' carried onjsimultaneouslyfby'ltheuse: of only tworefiectors,'instead of theordinaryjfour re.- flectorallocated atdistantpoints'. j The eliminationof interference between thetwo elements associated with each reflector j depends upon 1 a unique property of the 'screenjgratingnamely', I

that the screen grating actslajs'aplane reflector for ultra-short waves av ng their electrical field 7 parallel to the direction of the-wiresin the grate; ring and offers no obstacle v to waves having their electrical 'field perpendi'cul r to the direction of thesewires. l 1 y n One .of the, principal features, of the invention is the useof a parallellwire grating for separating two simultaneously.incidentpolarized waves hav ing' their planes of ;polarization- -inclined with ,-Another feature is the use of a; parallel-wire grating in combination with a reflector for super,- v posingoptically; but'not physically, the elements placed on either sideof the screen gratingr -Ano'th'er feature is the use Of" a parallel 'wire grating in combination with a reflectorfor superposing optically butnot physically, thetransinit -v v ting and-receiving elernentsj placed oneither side p 7i posing optically, but not physically, either two 'SCREENGRATINGFORTHEZS 1 *TWO =DJRECTIONAL TRANSMISSION'OF ULIBAeSHORTWAVES I Q Bene HQ Da i' lacrd PariiaFrance,assignerto inter a r nationalg0ornmunications; Laboratories, Inc, j

f. Y.) a oorperation of New York 7 transmitting ortwo'receiving eleme either side of; the. screen grating.

'of the following Ywell as frorn th appended claim "receptionbetweenitwo distant-points."j'A' and 3 transmitting elementji if'placed eras object tes is ordinary sense-it is necessary toidefine d y "by the reeeivi'n'g element 15;

parallel to the electrical field of the wave tr optical I elements capab18 of cog-operati v hysically; the elements fconiprisingIthe 'tra'ns- I mitting and'receiving antennae; M

IMUIITANEOUS r h a ei fll'a e r-ir ma. e efi i i" detailed "description, -t'aken' in n 7 eonnection with {the a com an :drawin A preferredernbodiment oi t e inventionfis I h i i i r w w i ch 'i ilira s c me? I I cally the arrangement of therefi ec'tors' and as'so i t e e ii s f p r s b r nsmiem a e 1' representftwo stations; located" at: remote-points; At station 'n'isshown a; reflectorwl'fl havinga andga receiving element'lfi placed at itsprinci '7 fGQllS. f AS, the term (principal iocusfis used ts I principal fo'cus, "Disposedbetweerfflthe tr tin 1mentandthe receiving element is a "grating'll having" pluralityofparallel w es, 5s;- 1

r2 and'l3;which are suitablyfastened to a gular insulating frame (not shownff T'Ihe d1 tion of t eparallelvwires 12 ;,l3,*etc, ofthelscr en grating is such that these 'wir esareflparallel electrical, field of waves radiating. from the tr jrnitting element 'li'an'dla re perpendicularfto the f electrical field oftthewaves adapted tobereeeived 1 reflector. Disposed Qbetweenf l the transmitting;

parallel wire screenpgraitingfl'l, similar" of the parallel wiresof, the-screen grating.

rnitted' by" transmitting element "1 and iis 'pe penolicular to the electrical field "off the wavesflfld adapted to be received jby the";receivingelee' ment 19,: v y

1 1 The reflectorsloand'lfi maybe par abolicrej flectors,'lenses;"'etc;,a d;' c f t m rb v mannerwide;

the screen gratingslll and 17,'ina

tion of a reflector having a principal and an ob-' ject focus, a transmitting antenna. element i placed at one focus' and a receiving antenna element placed at the other focus, anda polarizing grating disposed between said elements.

2. In an ultrashort wave system, the combina- L tion of a reflector -'havinga principal and an T object focus, a transmitting antenna element ,[10' disposed between said elementsfsaid grating placed at one focus,'a receiving antenna-element placed at the otherfocus, a polarizing grating comprising a plurality of parallel wires, having diameters small in'comparison with the length of ultrashortwaves and said wires being spaced from one another at distances likewise small in comparison with said wave lengths.

3. In an ultrashort wave system, the combination of a reflector having a principal and an object focus, a .transmitting antenna element 20 t t placed at the other focus, and a polarizing gratplaced at one focus, a receiving antenna element ing comprising a; plurality of parallel wires disposed between said elements in such a way that ;the direction of said wires is parallel to one, antenna element and is perpendicular to the other antenna element.

4'. In an ultrashort wave. system, thecombination of a reflector'having aprincipal and an object focus, a transmitting antenna element placed at one focus, a-receiving antenna element placed at'the other focus and a polarizing grating, equal in extent to at least the focal area of said reflector, disposed between sa'id elements.

5. In ultra-short wave systems, the combination of 'a reflector, a transmitting element placed" at the object focus and a receiving element placed at the principal focus of said reflector, a polarizing grating suitably disposedbetween said elev ments, said grating comprising a plurality of par-7" allelwires, the direction of said wires being parallel to the electrical field of waves radiated from said transmitting element and perpendicular to Y the electrical field of waves adapted to be received i by said receiving element.

" 45" I 6. In an ultra-short wave system providing sirality of parallel wires having their direction subto the other.

interference between said channels, the combinaflector, saidgrating comprising a pluralityofpar; I

antenna element placed at one'focus and 'a re allelwires which have diameters small in comparison with the le'ngth of ultra-short waves and which are spaced from one another at distances length. I

Inultra-short wave systems, the combina-;, tion of a reflector, a transmittingtelement placed at the principal focus and a receiving-element,

placed at the object focus ,of saidreflector, av polarizing grating disposed betweensaid anr r tennae elements, said grating comprising aplustantiallyperpendicular to the electrical field of waves radiated from said transmitting element of waves adapted to be received by said receiving 1 element,

multaneous two-channel communication without likewise small in comparison with jsaid wave-'' I and substantially parallelito the electrical field 8. In an ultra-short wave system,-the combina tion of a reflector having 'a principal andfanob-- ject focus, separate antennae elements for simule. taneous transmission and reception; respectively, each placed at one ofv said foci, and a polarizing grating, disposed between said antennae elements prevent-v ing interference between said antenna: elements l v j and co-operating with said reflector for by optically superposing said: elementsQ: I

9; In an ultra-short wave system, the combinajtion of a reflector having a: principal and an object focus, an antenna element at each focus";

and disposed normal to the axis of the reflector V and normal one to .the other, and 'abpolarized grating disposed between said elements andcom prising a plurality of wires extending in a direcj tion parallel to one antenna'element and normal RENE: H. DARBOR D Q 12'0- 

